Image processing apparatus, control method of image processing apparatus, and storage medium

ABSTRACT

To make it possible to easily determine a printed material of an electronic document proved to be an authentic original document and a copied material thereof. In a case where a printed material is copied, embedded information is extracted from a scanned image obtained by scanning the target printed material. Then, in a case where it is confirmed that the copy-target printed material is an authentic document, the printed material is printed and output by adding information indicating being a copied material thereto.

BACKGROUND OF THE INVENTION Field of the Invention

The technique of the present disclosure relates to a technique todistinguish between “copied material of an authentic original document”and “printed material of an authentic original document”.

Description of the Related Art

Conventionally, in the society in Japan and each country, a paperdocument has been handled as a formal authentic original document.However, with the development of the advanced information communicationssociety, the legal adjustment (electronic signature method), the reformof system, and the relaxation of regulations have been prompted so thatan electronic document can be handled as an authentic original documentand the technique to utilize/store an electronic document as anauthentic original document has also been implemented. In the socialbackground such as this, at present, an electronic document is handledas an authentic original document and it has become not uncommon that aprinted material on which it is printed is handled as its copy (forexample, a copy of certificate of residence). Japanese Patent Laid-OpenNo. 2003-084962 has disclosed a technique to guarantee authenticity of adocument by making different the printing method between a case where anelectronic document proved to be an authentic original document isprinted and the other cases.

The technique of Japanese Patent Laid-Open No. 2003-084962 does notsuppose a case where a printed material of an electronic document provedto be an authentic original document is further copied by using a copymachine and it is not possible to deny the authenticity of a printedmaterial obtained by copying. That is, in a case where a “printedmaterial of an authentic original document” and a “copied material of anauthentic original document” obtained by copying the “printed materialof an authentic original document” exist in a mixed manner, it isdifficult to distinguish between them.

SUMMARY OF THE INVENTION

The image processing apparatus according to the present disclosure is animage processing apparatus having a copy function and including: amemory that stores a program; and a processor that executes the programto perform: obtaining a scanned image by scanning a copy-target printedmaterial; extracting embedded information from the scanned image;generating an image to be printed based on the scanned image; andperforming print processing using the image to be printed, wherein inthe generating, in a case where it is confirmed that the copy-targetprinted material is an authentic document by embedded informationextracted in the extracting, an image to be printed that is the scannedimage to which information indicating being a copied material is addedis generated.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration of a printing system;

FIG. 2 is a flowchart showing a flow in a case where an electronicdocument of an authentic original document is printed;

FIG. 3 is a diagram showing an example of a page image;

FIG. 4A and FIG. 4B are each a diagram showing an example of a mask:

FIG. 5A and FIG. 5B are each a diagram showing a pattern that is formedby a mask;

FIG. 6A and FIG. 6B are each a diagram showing an example of a mask;

FIG. 7A and FIG. 7B are each a diagram showing a pattern that is formedby a mask;

FIG. 8 is a flowchart showing a flow in a case where a printed materialof an authentic original document is copied:

FIG. 9 is a diagram showing a characteristic of a spatial frequency of apattern used for embedment;

FIG. 10 is a flowchart showing details of falsification checkprocessing;

FIG. 11 is a diagram showing an example of an image to which informationindicating being a copy of a “printed material of an authentic originaldocument” is added:

FIG. 12 is a diagram showing an example of an image to which informationindicating being a copy of a “printed material of an authentic originaldocument” is added; and

FIG. 13A and FIG. 13B are explanatory diagrams in a case where documentID information is embedded by being turned into a QR code (registeredtrademark).

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, with reference to the attached drawings, the presentdisclosure is explained in detail in accordance with preferredembodiments. Configurations shown in the following embodiments aremerely exemplary and the present disclosure is not limited to theconfigurations shown schematically.

In the present specification, it is assumed that an “authentic origindocument” means an electronic document (digital document) that isregistered/managed along with information indicating that the contentsthereof are authentic and a “printed material of an authentic originaldocument” means a printed material that is printed by using data of theelectronic document. Consequently, an official document, for example,such as the “copy of certificate of residence” described previously,which is issued by a public office, corresponds to the “printed materialof an authentic original document”. Further, it is assumed that a“copied material of an authentic original document” means a printedmaterial obtained by copying the “printed material of an authenticoriginal document” by an image processing apparatus equipped with a copyfunction. Consequently, what is obtained by copying, for example, theabove-described “copy of certificate of residence” corresponds to the“copied material of an authentic original document”.

First Embodiment <System Configuration>

FIG. 1 is a block diagram showing the configuration of a printing systemaccording to the present embodiment. As shown in FIG. 10, this printingsystem has an MFP (Multi Function Printer) 10 as a printing apparatusand a PC 20 as a host apparatus thereof. The MFP 10 has a plurality offunctions, such as the function as a printer and the function as ascanner, and also has the copy function that performs both the functionsin conjunction with each other. It may also be possible for the MFP 10further to have the function to store/transmit printing-target imagedata and the function to transmit and receive a FAX. In the following,the hardware configuration of each of the MFP 10 and the PC 20 isexplained.

The MFP main body 10 mainly includes the following elements. A CPU 11 isa central processing unit that centralizedly controls the entire MFP 10and performs, for example, copy processing and the like, to be describedlater, in accordance with programs stored in a ROM 13 or a RAM 12. TheRAM 12 is a volatile storage and temporarily stores programs and data.Further, the ROM 13 is a nonvolatile storage and stores table data andprograms, which are used in various kinds of processing, to be describedlater. A DATA TRANSFER I/F 14 controls transmission and reception ofdata with the PC 20. A HEAD Controller 15 controls the heating operationof a heater mounted on a print head, not shown schematically, based onprint data and ejects ink. An Image Processing Accelerator 16 is acentral processing unit capable of performing image processing fasterthan the CPU 11. The Image Processing Accelerator 16 is not necessarilyrequired and it may also be possible to perform creation processing ofthe above-described table parameters and the image processing only bythe processing by the CPU 11 in accordance with the specifications ofthe printer and the like. A SCANNER Controller 17 performs lightemission control of an LED mounted on a scanner unit, not shownschematically, obtaining of light quantity information from the scannerunit, write control to the RAM 12, and so on. Due to this, an image of adocument set on a document table, not shown schematically, is read. AMOTOR Controller 18 controls a plurality of motor units, not shownschematically, and moves the print head relative to a printing medium,moves the scanner unit relative to a document, and so on. Theconfiguration of the MFP 10 is not limited to that shown schematicallyand for example, the configuration may comprise a network interface thatconnects to an external network and performs communication with anotherexternal PC and the like.

The PC 20 mainly includes the following elements. A CPU 21 is a centralprocessing unit that centralizedly controls the entire PC 20 andperforms, for example, print processing of an authentic originaldocument, to be described later, in accordance with programs stored inan HDD 23 or a RAM 22. The RAM 22 is a volatile storage and temporarilystores programs and data. Further, the HDD 23 is a nonvolatile storageand similarly stores programs and data. A DATA TRANSFER I/F 24 controlstransmission and reception of data with the MFP 10. As the connectionmethod of the data transmission and reception, it is possible to usewired connection, such as USB, IEEE 1394, and LAN, and wirelessconnection, such as Bluetooth and WiFi. A KEYBOARD MOUSE I/F 25 is aninterface that controls an HID (Human Interface Device), such as akeyboard and a mouse. A DISPLAY I/F 26 performs display control in adisplay, not shown schematically. A NETWORK I/F 27 connects the PC to anexternal network and performs communication with a single external PC ora plurality of external PCs, and makes a request for collation of adocument ID, a request for results, a request for document data, and thelike.

<Print Processing of Authentic Original Document>

Following above, a flow in a case where an electronic document, which isan authentic original document, is printed is explained with referenceto the flowchart in FIG. 2. The series of processing shown in theflowchart in FIG. 2 is started by a user selecting an electronicdocument that is a printing target and giving instructions to performprinting accompanied by embedment of information indicating authenticitythereof via a UI of a predetermined printing application installed inthe PC 20. In the following explanation, symbol “S” means a step.

At S201, data of an electronic document designated as a printing targetis obtained. In the present embodiment, electronic documents of variousauthentic original documents are stored/managed by an external PC, notshown schematically. The PC 20 transmits a request to obtain a specificelectronic document to the external PC via the NETWORK I/F 27 andreceives and obtains data for printing a designated electronic document,specifically, PDL data from the external PC. Here, PDL is theabbreviation of Page Description Language and consists of a set ofdrawing commands for each page. The kinds of drawing command are definedfor each PDL specification and in the present embodiment, the followingthere kinds are used as an example.

TEXT drawing command: (X1, Y1, color, font information, character stringinformation)

BOX drawing command: (X1, Y1, X2, Y2, color, fill pattern)

IMAGE drawing command: (X1, Y1, X2, Y2, image file information)

In addition to the above-described three kinds, the DOT drawing commandto draw a dot, the LINE drawing command to draw a line, the CIRCLEdrawing command to draw a circular arc, and the like exist and thesedrawing commands are used in accordance with use. In general, as PDLthat is used frequently, PDF (Portable Document Format) proposed byAdobe Inc., XPS proposed by Microsoft Corporation, HP-GL/2, proposed byHP Inc., and the like exist.

FIG. 3 is a diagram showing an example of an image corresponding to onepage of an electronic document (in the following, called “page image”).Here, it is assumed that the size of a page image 300 shown in FIG. 3 ishorizontal width of 600 pixels×vertical width of 900 pixels. In thefollowing, PDL corresponding to the page image 300 is shown.

<PAGE = 001>  <TEXT> 50, 50, 200, 100, BLACK, STD-18,“ABCDEFGHIJKLMNOPQR” </TEXT>  <TEXT> 50, 100, 200, 150, BLACK, STD-18,“abcdefghijklmnopqrstuv” </TEXT>  <TEXT> 50, 150, 200, 825, BLACK,STD-18, “1234567890123456789” </TEXT>  <BOX> 50, 300, 200, 450, GRAY,STRIPE </BOX>  <IMAGE> 250, 300, 550, 800, “PORTRAIT.jpg” </IMAGE></PAGE>

<PAGE=001> in the first row of the above-described PDL is a tagindicating the page number. Normally, PDL is designed so as to becapable of describing a plurality of pages and in PDL, a tag indicatingthe divider of a page is described. The example described aboveindicates that the first page continues up to </PAGE> in the tenth row.In a case where the second page exists, <PAGE=002> is described. From<TEXT> in the second row up to </TEXT> in the third row is the TEXTdrawing command. In the TEXT drawing command, the first two coordinatesindicate coordinates (X1, Y1) of the top left of the drawing area andthe two subsequent coordinates indicate coordinates (X2, Y2) of thebottom right of the drawing area. Following this, it is described thatthe color is “BLACK (black: R=0, G=0, B=0)”, the character font is “STD(standard)”, the character size is 18-point, and the character string tobe drawn is “ABCDEFGHIJKLMNOPQR”. From <TEXT> in the fourth row up to</TEXT> in the fifth row and from <TEXT> in the sixth row up to <TEXT>in the seventh row are also the TEXT drawing commands. The characterstrings to be drawn correspond to “abcdefghijklmnopqrstuv” and“1234567890123456789”, respectively. From <BOX>up to </BOX> in theeighth row is the BOX drawing command and the first two coordinatesindicate the coordinates (X1, Y1) of the top left, which is the startingpoint of drawing, and the two subsequent coordinates indicate thecoordinates (X2, Y2) of the bottom right, which is the endpoint ofdrawing. Following this, as the color, “GRAY (gray: R=128, G=128,B=128)” is designated and as the fill pattern, “STRIPE (stripe pattern)”is designated. The ninth row is the IMAGE drawing command. The first twocoordinates indicate the coordinates (X1, Y1) of the top left of thedrawing area and the two subsequent coordinates indicate the coordinates(X2, Y2) of the bottom right of the drawing area. Then, it is describedthat the file name of the image existing in the designated drawing areais “PORTRAIT.jpg”. Here, “.jpg” is an extension, indicating that thefile is a JPEG file, which is a generally prevailing image compressionformat. Then, </PAGE> in the tenth row is the description indicatingthat the drawing of the page is completed. In many cases, in documentdata that is obtained actually, font data and an image file are added tothe PDL data and integrated therein. The reason is that in a case wherefont data and an image file are managed separately, it is not possibleto form the text/image portions by the drawing command alone andinformation is not sufficient to form a printing-target image. At thisstep, document data including the PDL data such as this is obtained byaccessing the external PC.

At S202, information indicating authenticity of a printing-targetelectronic document is obtained. In the present embodiment, it isassumed that a request to obtain information indicating authenticity ofan electronic document is transmitted to the above-described external PCvia the NETWORK I/F 27 and the information is received/obtained. As theinformation indicating authenticity of an electronic document, here,document ID information is used. The document ID information isinformation of a predetermined number of bits (32 bits in the presentembodiment), which is calculated using a hash function based on theabove-described document data (data in which PDL data, font data, andimage file are integrated). In a case where even one byte of the digitaldata constituting the electronic document is changed, different documentID information is calculated as a result, and therefore, a uniquedocument ID is associated with one electronic document. It may also bepossible to reduce the falsification risk of document ID information bystoring/managing electronic document files and document ID informationby the collaboration of a plurality of external PCs and adopting asystem configuration like a block chain. Further, in a case where the PC20 has sufficient resources and it is possible to perform management ofdocument ID information within the PC 20, it is also possible to performcollation processing internally.

At S203, rendering processing is performed based on the document dataobtained at S201. In this rendering processing, by performing eachdrawing command included in the PDL data, image data in the bitmapformat, which consists of color information for each pixel, isgenerated. For example, in a case of the page image 300 in FIG. 3described above, a bitmap image of 600×900 pixels is generated. In thepresent embodiment, it is assumed that R, G, and B of each pixel of thebitmap image is represented by eight bits, that is, in 256 tones.

At S204, for the bitmap image generated at S203, processing to embed thedocument ID information obtained at S202 is performed. The processing toembed document ID information in a bitmap image is called “embeddingprocessing”, “embedding encode processing” and the like. As regards theprinted material obtained by printing a bitmap image for which theembedding processing has been performed, in a case where the printedmaterial is copied, it is made possible to determine whether or not thecopy-target printed material is the “printed material of the authenticoriginal document” by extracting (decoding) the document ID informationfrom the scanned image of the printed material.

Originally, handling information in an information processing apparatus,such as the PC 20, is equivalent to handling binary data. Binary data isinformation that is represented by a combination of “0” and “1” and bythe information represented by “0” or “1” such as this is connectedcontinuously, the combination of “0” and “1” becomes to have a specificmeaning. For example, in a case where an English word “hello” is handledas binary data, in an example of Shift JIS, which is one of charactercodes, the alphabet “h” corresponds to binary data of “01101000”.Similarly, “e” corresponds to “01100101”, “1” corresponds to “01101100”,and “o” corresponds to binary data of “01101111”. That is, it ispossible to represent the character string “hello” as binary data of“0110100001100101011011000110110001101111”. On the contrary, in a casewhere it is possible to obtain the binary data“0110100001100101011011000110110001101111”, it is possible to obtaincharacter information representing the English word “hello”. Based onthe notion such as this, it can be seen that it is possible to implementembedding by embedding predetermined data within an image in such amanner that “0” or “1” can be determined.

<Embedding Processing>

FIG. 4A and FIG. 4B are each an example of a mask consisting of 8×8pixels, which is used for generating “0” and “1”. FIG. 4A is a mask forgenerating “0” and FIG. 4B is a mask for generating “1”. By adding thevalue within the mask to the pixel value in a bitmap image, it ispossible to give a pattern having periodicity to each area of 8×8 pixelswithin the image. As described above, in the bitmap image of the presentembodiment, one color is represented by eight bits and one value between0 and 255 is allocated to each pixel. A value outside the range between0 and 255 cannot be used as image data, and therefore, in a case whereaddition results in a value less than 0 or a value larger than or equalto 256, it is generally performed that the value of the addition resultsis replaced with 0 or 255 and thereby included within the valid range.In the masks in FIG. 4A and FIG. 4B, the pixel value is changed by “−10”or “0”, but in a case where all the pixel values within the bitmap imagecorresponding to the mask area are “0”, all the values in the area are“0”. Here, the case where one color is represented by eight bits isexplained, but the number of bits is not limited to this. In a casewhere a digital image is handled, despite that one color is representedby any number of bits, a valid range exists and it is not possible tochange a value to another outside the range.

FIG. 5A and FIG. 5B are each a diagram visually showing what kind ofpattern is formed in the bitmap image by the mask in each of FIG. 4A andFIG. 4B described above. The position of “−10” in the mask in each ofFIG. 4A and FIG. 4B is represented in solid black and the position of“0” is represented by hatching. As can be seen from FIG. 5A and FIG. 5B,in the bitmap image to which the mask has been applied, a diagonal lineextending in the lower-leftward direction appears as a “patternrepresenting 0” and a diagonal line extending in the lower-rightwarddirection appears as a “pattern representing 1”.

Here, a pseudo code at the time of alternately applying the mask in FIG.4A and the mask in FIG. 4B to the entire bitmap image is shown below.

01:  int i, j, k, l; 02:  int width = 600, height = 900; 03:  unsignedchar *data = image data; 04:  int **maskA = mask data; 05:  bool isMaskA= true; 06:  for (j = 0; j < height; j+=8){ 07:   for (i = 0; i < width;i+=8){ 08:    for (k = 0; k < 8; k++){ 09:     for (1 = 0; 1 < 8; l++){10:      if (isMaskA == true){ 11:  data [(i+k)+(j+l)*width] +=maskA[k][l]; 12:      } 13: } 14:    } 15:   } 16:  }

In the present embodiment, embedment of the above-described pattern datais performed only for the B value among the RGB values each pixel of thebitmap image has. The reason is that in a case where printing isperformed for the paper white area of a sheet in the four kinds of inkof CMYK, the capability of being visually recognized of Y ink is lowerthan that of each ink of CMK. At the time of embedding, it is preferableto cause the above-described pattern to be embedded to affect theoriginal image as slightly as possible, that is, cause theabove-described pattern to be visually recognized as less as possible.RGB, which are the three primary colors of light, and CMY, which are thethree primary colors of color, are in a complementary color relationshipand R and C, G and M. and B and Y are in opposite hues, respectively.This means that in a case where modulation is performed for the B valueamong the RGB values, the amount of use of Y ink largely changes.Consequently, in the present embodiment, control is performed so thatthe variation in density of Y ink becomes large by performing modulationfor only the B value among the RGB values.

Here, in the case of the page image 300 shown in FIG. 3 describedpreviously, the paper white area is sufficiently large and the areaexcept for a TEXT drawing area 301, a BOX drawing area 302, and an IMAGEdrawing area 303 is the paper white area. In this case, it may happenthat it is not possible to perform embedment of the pattern datasuccessfully for each drawing area except for the paper white area withthe masks shown in FIG. 4A and FIG. 4B. For example, for the drawingarea of solid black (R=0, G=0, B=0), the results after embedment are thesame solid black (R=0, G=0, B=0). Consequently, in a case whereembedment of pattern data is performed for the area other than the paperwhite area, particularly for the image drawing area, it is preferable toapply, for example, masks as shown in FIG. 6A and FIG. 6B. The masks inFIG. 6A and FIG. 6B are those that change each pixel of the bitmap imageby “−10”, “0”, and “+10”. In the case of the masks in FIG. 6A and FIG.6B, even on a condition that all the pixel values of the bitmap imagecorresponding to the mask area are “0”, the pixel value in the area iseventually “0” or “+10”. Consequently, it is possible to performembedment of pattern data for all the pixels within the bitmap image.FIG. 7A and FIG. 7B are diagrams visually showing what kinds of patternsare given to the bitmap image by the masks in FIG. 6A and FIG. 6B. Theposition of “−10” in the mask in each of FIG. 6A and FIG. 6B isrepresented in solid black, the position of “0” is represented byhatching, and the position of “+10” is presented in solid white. As canbe seen from FIG. 7A and FIG. 7B, in the bitmap image after the mask hasbeen applied, a plurality of diagonal lines extending in thelower-leftward direction whose densities are different appears as a“pattern representing 0” and a plurality of diagonal lines extending inthe lower-rightward direction whose densities are different appears as a“pattern representing 1”. In the TEXT drawing area and in the BOXdrawing area, normally, the possibility that the many paper white areasexist is strong, and therefore, it is preferable to apply the masks inFIG. 4A and FIG. 4B. However, even in the TEXT drawing area and in theBOX drawing area, depending on the designated color, the thickness of acharacter and the like, there is a case where the masks in FIG. 6A andFIG. 6B are appropriate. Further, there is a case where even the IMAGEdrawing area is very close to the paper white area. Because of this, itmay also be possible to determine the type of mask that is applied byobtaining the density histogram in each drawing area, and so on. Forexample, in a case where the maximum value of RGB values is larger thana threshold value, the masks in FIG. 4A and FIG. 4B are applied and in acase where it is less than or equal to the threshold value, the masks inFIG. 6A and FIG. 6B are applied, and so on. Alternatively, in a casewhere the input color space is L*a*b*, it may also be possible to switchmasks to be applied by comparing the L* value representing luminancewith a threshold value. Due to this, it is made possible to implementsecure embedment.

Explanation is returned to the flowchart in FIG. 2.

At S205, an image to be printed is generated based on the bitmap imagegenerated at S204 and for which embedding has been performed (in thefollowing, described as “embedded image”). For the generation of theimage to be printed, it is sufficient to use a publicly known method. Inthe present embodiment, it is assumed that for each pixel of an embeddedimage, each piece of processing, such as color conversion processing,color separation processing, output characteristic conversionprocessing, and quantization processing, is performed. In the following,each piece of processing is explained briefly.

<<Color Conversion Processing>>

The color conversion processing is processing to convert the pixelvalues (RGB values) of an embedded image into values that can bereproduced appropriately by the MFP 10. Generally, the color valuedesignated in the drawing command of PDL is the color value that is setso that the color value can be represented appropriately on a display,and therefore, in a case where the color value is output as it is by aprinter, a tint different from that seen on the display is output.Consequently, the color conversion processing for absorbing thedifference in color therebetween is performed. For this color conversionprocessing, a three-dimensional lookup table (LUT) is used, whichassociates a combination of preferred output pixel values (Rout, Gout.Gout) with a combination of input pixel values (Rin, Gin, Bin) in anembedded image. Here, each of the input values Rin, Gin, and Bin has 256tones. Because of this, it is ideal to prepare a table(Table1[256][256][256][3]) having a total of 16,777,216 (256×256×256)combinations of the output values (Rout, Gout, Bout) shown below.

Rout = Table1[Rin][Gin][Bin][0]Gout = Table1[Rin][Gin][Bin][1]Bout = Table1[Rin][Gin][Bin][2]

However, it may also be possible to use publicly known devices to reducethe table size, such as reducing the number of grids of the LUT from 256grids to, for example, 16 grids or the like and determining the outputvalue by interpolating the table value between grids.

<<Color Separation Processing>>

The color separation processing is processing to convert Rout, Gout, andBout, which are the output values of the color conversion processing,into the output values of each ink color (here, four colors of CMYK)that is printed on a sheet by the ink jet method. There are also variousimplementation methods for this color separation processing. In thepresent embodiment, a three-dimensional lookup table(Table2[256][256][256][4]) is used, which associates a combination ofink color pixel values (C. M. Y. K) shown below with a combination ofthe above-described output pixel values (Rout, Gout, Bout).

C = Table2[Rout][Gout][Bout][0]M = Table2[Rout][Gout][Bout][1]Y = Table2[Rout][Gout][Bout][2]K = Table2[Rout][Gout][Bout][3]

At this time, it is preferable only for the Y value among the CMYKvalues corresponding to the results of performing modulation for thepaper white area by the embedding processing at S204 to have a valuelarger than 0. In more detail, it is preferable to set the CMYK valuescorresponding to the area in which the pixel values of R=255, G=255, andB=255 are converted into the pixel values of R=255, G=255, and B=245 sothat the Y value is a value exceeding 0 and the CMK values are valuessmaller than the Y value and close to 0. The reason is that, asexplained at S204, it is desired to reduce the capability of beingvisually recognized of the pattern that is embedded. As in the case ofthe above-described color conversion processing, it may also be possibleto use publicly known devices to reduce the table size.

<<Output Characteristic Conversion Processing>>

The output characteristic conversion processing is processing to convertthe density of each ink color of CMYK into a printed dot number ratio.Specifically, for example, the density of each color having 256 tones isconverted into a dot number ratio of each color having 1,024 tones. Forthis output characteristic conversion processing, a one-dimensionallookup table (Table3[4][256]) is used, which sets printed dot numberratios (Cout, Mout, Yout, Kout) shown below, corresponding to thedensity of each ink color.

Cout = Table3[0][C]Mout = Table3[1][M]Yout = Table3[2][Y]Kout = Table3[3][K]

As in the case of the color conversion processing and the colorseparation processing, which are described above, it may also bepossible to use publicly known devices to reduce the table size.

<<Quantization Processing>>

The quantization processing is processing to convert the above-describedprinted dot number ratios (Cout, Mout, Yout, Kout) of each ink colorinto quantized values (Cdot, Mdot, Ydot, Kdot) shown below, representingON or OFF of the printed dot of each pixel.

Cdot = Halftone[Cout][x][y]Mdot = Halftone[Mout][x][y]Ydot = Halftone[Yout][x][y]Kdot = Halftone[Kout][x][y]

The above values are quantized values in a case of the dither method andby making a comparison with the threshold value within the dither matrixin accordance with each pixel position, it is possible to obtain thevalue representing ON or OFF of the printed dot of each ink color. Here,the occurrence probability of each printed dot is Cout/1,023,Mout/1,023, Yout/1,023, and Kout/1,023. The method of the quantizationprocessing is not limited to the dither method and it may also bepossible to use another method, for example, such as the error diffusionmethod.

By performing each piece of processing explained above in order, animage to be printed is generated from an embedded image. Explanation isreturned to the flowchart in FIG. 2.

At S206, the data of the image to be printed that is generated at S205is transmitted along with printing instructions thereof to the MFP 10 oranother printer, not shown schematically, and print processing isperformed by the printer at the transmission destination.

The above is the flow until the printed material of the authenticoriginal document is generated. In the embedding processing (S204),modulation is performed for the B value among the RGB values in thepresent embodiment, but it may also be possible to perform modulationfor the CMYK values. In this case, the pixel values of the paper whitearea are Y=0, M=0, C=0, and K=0, and therefore, it is necessary to use apositive value for modulation. In the case of the masks illustrated inFIG. 4 and FIG. 6 described previously, it is sufficient to invert thesign of the value for which modulation has been performed within themask, that is, invert “−10” to “+10” and “+10” to “−10”. In a case wheremodulation has been performed for the CMYK values as described above,the controllability at the time of limiting the ink that is attached tothe paper white area only to Y ink becomes high. On the other hand, in acase where modulation is performed for the RGB values, thecontrollability to suppress the variation in hue at the time ofperforming embedment into the image drawing area becomes high.Consequently, it is preferable to select a preferred modulation methodin accordance with the characteristic of the printing process, such aselectrophotography and ink jet, the paper white/text/image area ratiowithin the printing-target page image, and the like.

<Copy Processing of “Printed Material of Authentic Original Document”>

Following the above, the flow at the time of copying the “printedmaterial of the authentic original document”, which is the resultantmaterial of the print processing of the authentic original materialdescribed above, is explained with reference to the flowchart in FIG. 8.The series of processing shown in the flowchart in FIG. 8 is started bya user setting the printed material of the authentic original documenton a document table, not shown schematically, via the UI (UserInterface) of the MFP 10 and giving copy instructions. In the followingexplanation, symbol “S” means a step.

First, at S811, the copy-target printed material that is set to the MFP10 is read by a built-in scanner unit (not shown schematically). In thisreading of the printed material, the printed material placed on thedocument table is irradiated with LED light and the reflected light isconverted into an analog electric signal by an image capturing element,such as CCD, opposed to each pixel.

At next S812, the analog electric signal obtained at S811 is digitizedand a bitmap image in the RGB color space is obtained. At this time, foreach pixel of the bitmap image, image processing, such as MTF correctionprocessing, input correction processing, shading correction processing,and color conversion processing, is performed. In the following, eachpiece of processing is explained briefly.

<<MTF Correction Processing>>

The MTF (Modulation Transfer Function) correction processing iscorrection processing relating to the resolution among the readingperformances of the scanner unit. In a case where an image is readoptically by the scanner unit, due to the shift from the position infocus, the limit of the performance of the lens itself, and the like,the image is blurred, and therefore, restoration to a certain extent isperformed by filter processing and the like. At this time, in a casewhere enhancement processing so strong that perfect restoration willresult is performed, image impairment, such as the white area andenhancement of the image noise/dust pixel, becomes conspicuous, andtherefore, it is necessary to design the filter strength by takingbalance between image improvement and impairment. The following is anexample of an edge enhancement filter that quintuples the center portionof the image and multiplies the values of the pixels located above,below, to the left, and to the right by −1.

R^(′)[x][y] = R[x][y] × 5 − R[x − 1][y] − R[x + 1][y] − R[x][y − 1] − R[x][y + 1]G^(′)[x][y] = G[x][y] × 5 − G[x − 1][y] − G[x + 1][y] − G[x][y − 1] − G[x][y + 1]B^(′)[x][y] = B[x][y] × 5 − B[x − 1][y] − B[x + 1][y] − B[x][y − 1] − B[x][y + 1]

<<Input Correction Processing>>

The input correction processing is processing to convert the outputvalue of the CCD (image capturing element), which is originally a photonquantity, into the lightness matching with the sensitivity of the humaneyes. Due to this, for example, R′G′B′ signals of each color having4,096 tones are converted into color intensity values (R″, G″, B″) ofeach color having 1,024 tones. For this conversion, a one-dimensionallookup table (Table4[4][4096]) shown below is used, which sets thepreferred printed dot number ratio for the density of each color.

R^(″) = Table4[0][R^(′)]G^(″) = Table4[1][G^(′)]B^(″) = Table4[2][B^(′)]

However, it may also be possible to use publicly known devices to reducethe table size, such as reducing the number of grids of the LUT from4,096 grids to, for example, 256 grids or the like and determining theoutput value by interpolating the table value between grids.

<<Shading Correction Processing>>

The shading correction processing is processing to reduce thecolor/density unevenness caused by the difference in reading sensitivityat each pixel position resulting from the variation of manufacturing andthe variation of assembling of the parts, such as the lens, LED and CCD,which configure the scanner device. For example, R″G″B″ signals of eachcolor having 1,024 tones are converted into color intensity values (R′″,G′″, B′″) of each color having 256 tones. For this conversion, aone-dimensional lookup table (Table5[x][3][1024]) shown below is used,which specifies the density adjustment value for each pixel position inthe X-direction (direction in which the scanner lens is arranged).

R^(′)^(′)^(′) = Table5[x][0][R^(″)]G^(′)^(′)^(′) = Table5[x][1][G^(″)]B^(′)^(′)^(′) = Table5[x][2][B^(″)]

As in the case of the input correction processing described above, itmay also be possible to use publicly known devices to reduce the tablesize.

<<Color Conversion Processing>>

The color intensity values (R′″, G′″, B′″) of each color having 256tone, which are calculated by the processing so far, are values uniqueto the scanner unit in contrast to those at the time of printing. Thecolor conversion processing here is processing to convert the valuesunique to the scanner unit into preferred RGB values (Rout, Gout, Boutvalues) for display on the display device. Here, each of R′″, G′″, andB′″, which are input values, has 256 tones. Consequently, for thisconversion, a three-dimensional lookup table (Table6[256][256][256][3])shown below is used, having the output values of a total of 16,777,216(256×256×256) combinations.

Rout = Table1[R^(′)^(′)^(′)][G^(′)^(′)^(′)][B^(′)^(′)^(′)][0]Gout = Table1[R^(′)^(′)^(′)][G^(′)^(′)^(′)][B^(′)^(′)^(′)][1]Bout = Table1[R^(′)^(′)^(′)][G^(′)^(′)^(′)][B^(′)^(′)^(′)][2]

As in the case of the input correction processing and the shadingcorrection processing, which are described above, it may also bepossible to use publicly known devices to reduce the table size. In thismanner, a bitmap image is obtained.

At S813 that follows, for the bitmap image obtained at S812, processingto extract document ID information is performed. Specifically,processing to determine whether the pattern indicating “0” or “1”, whichis described previously, is formed within the bitmap image for eachpredetermined area (here, 8×8 pixels) and extract information on asequence represented by “0” and “1” is performed. By repeatedly applyingthis to the entire bitmap image, the document ID information embedded bythe embedding processing at the time of printing of the authenticoriginal document is decoded. There is a case where the informationembedded by the embedding processing is called “embedded information”.Here, decoding processing of embedded information is explained indetail.

<<Decoding Processing of Embedded Information>>

First, the position at which embedded information is embedded within theobtained bitmap image is detected. It is possible to detect theembedment position by analyzing the spatial frequency characteristic foreach unit area (here, area of 8×8 pixels). FIG. 9 is a diagram showingthe characteristic of the spatial frequency of the pattern used forembedment. The horizontal axis represents the frequency in thehorizontal direction and the vertical axis represents the frequency inthe vertical direction and as the position becomes more distant from theorigin, the frequency of the area becomes higher. In the presentembodiment, the two kinds of pattern corresponding to “0” and “1”,respectively, are embedded in the image (see FIG. 5 and FIG. 7 describedpreviously). At that time, subtraction of a value of “10” is performedfor the B component of each color component of RGB (in the case of themask in FIG. 4. In the case of the mask in FIG. 6, addition andsubtraction). Due to this, for example, the pattern extending in thelower-leftward direction that is formed within the image by the mask inFIG. 4A causes a large power spectrum to occur on a line A02. Similarly,the pattern extending in the lower-rightward direction that is formedwithin the image by the mask in FIG. 4B causes a large power spectrum tooccur on a line A01. Because of this, by detecting this power spectrum,it is possible to extract the data of “0” or “1”. By performing edgedetection as the preprocessing of the power spectrum detection, it isalso possible to enhance the power spectrum.

The data extraction by the above-described frequency analysis requiresaccurate cutout of the analysis area from the image data, and therefore,processing to correct the shift in the coordinate position is alsoperformed. For example, first, the cutout of the unit area from thebitmap image and the frequency analysis are repeated in the horizontaland vertical directions while shifting the pixel one by one. In a caseof the image size whose horizontal width is 600 pixels and whosevertical width is 900 pixels, the cutout and the frequency analysis arerepeated a total of 64 times. Then, the position at which the spectrumis strongest is taken as the reference position of cutout. Then, byextracting the embedded information based on the reference position, itis possible to obtain the embedded sequence of “0” or “1” with a highaccuracy.

In the present embodiment, as explained at S204, the embeddedinformation that is the target of embedment is data of text whosecharacter codes are written in numerical values by “Shift JIS”. In thiscase, in the single-byte code (half-width character) of Shift JIS, forexample, the alphabet “h” corresponds to binary data “01101000”, “e” to“01100101”, “1” to “01101100”, and “o” to “01101111”, respectively.Consequently, in a case where the extracted sequence of embeddedinformation is “0110100001100101011011000110110001101111”, the characterstring “hello”, which is the English word, is obtained. In this manner,the document ID information embedded as embedded information isextracted.

Explanation is returned to the flowchart in FIG. 8.

At S814 that follows, whether or not the extraction of document IDinformation has succeeded at S813 is determined. In a case where theextraction of document ID information has succeeded, the processingadvances to S815 and in a case where the extraction has failed, theprocessing advances to S820. Here, as the case where the extractionfails, there are considered two possibilities as follows. The firstpossibility is a case where document ID information has not originallybeen embedded in the copy-target printed material itself (possibility1). The other is a case where document ID information has been embeddedin the copy-target printed material, but it is not possible to correctlydetect the predetermined pattern representing embedded informationbecause the printed material is stained, handwritten characters areadded later, and the like (possibility 2). Here, in a case ofpossibility 1, the processing may advance to S820 without performinganything. On the other hand, in a case of possibility 2, it may also bepossible to give a notification to a user by displaying a message or thelike to the effect that “the authentic document (printed material of theauthentic original document) in which document ID information isembedded is about to be copied”. Due to this, it is possible for theuser to know that he/she is going to copy a printed material having thepossibility of being not authentic and the user is given a chance toselect abortion of the copy work or the like. For example, in a casewhere the results obtained by the extraction processing are not lessthan one bit and not more than 31 bits among the document ID informationof a total of 32 bits, it is sufficient to determine possibility 2 andgive the notification such as this. There may be a case where onepattern similar to the above-described predetermined pattern is includedwithin the image by chance. In view of the rare case such as this, it ispreferable to determine possibility 1 in a case where only less than 16bits, which are half 32 bits, can be extracted and determine possibility2 in a case where not less than 16 bits and not more than 31 bits areextracted.

At S815 that follows, collation processing of the document IDinformation that has been extracted successfully is performed. In thepresent embodiment, as in the document ID information obtainingprocessing at S202, it is assumed that the MFP 10 accesses the externalPC and makes a request for collation and obtains collation results.Specifically, it is assumed that the MFP 10 transmits a request forcollation of whether the extracted document ID information is validinformation that is registered formally via a network i/F, not shownschematically, and receives/obtains collation results from the externalPC. In a case where the MFP 10 has sufficient resources and can performmanagement of document ID information within the MFP 10, it is alsopossible to perform collation processing within the MFP 10.

Next, at S816, the processing is branched in accordance with whether ornot the above-described collation results indicate that the document IDinformation extracted at S813 is valid information registered formally.In a case where the document ID is valid, the processing advances toS817 and in a case where the document ID is invalid, the processingadvances to S820. Here, in a case where the document ID is invalid, itmay also be possible to give a notification to a user by displaying amessage or the like to the effect that “an unauthentic document whosedocument ID is invalid is about to be copied”. Due to this, the user isgiven a chance to select abortion of the copy work or the like.

At S817, processing to check whether or not the copy-target printedmaterial has been falsified (falsification check processing) isperformed. A rough flow of this falsification check processing is asfollows. First, the MFP 10 transmits a request to obtain document dataalong with document ID information to the external PC via a network I/F,not shown schematically. Then, the MFP 10 receives/obtains document data(PDL data) associated with the document ID information from the externalPC and performs rendering processing for the document data. Theprocessing up to this rendering processing is the preprocessing. Then,the MFP 10 determines the presence/absence of falsification by comparingthe bitmap image obtained by the rendering processing and the bitmapimage obtained at S812. Here, along another flowchart shown in FIG. 10,the falsification check processing is explained in detail. In theexplanation of the flow in FIG. 10, the bitmap image obtained by therendering processing is described as “rendering image” and the bitmapimage obtained by the document reading processing is described as“scanned image”.

<Details of Falsification Check Processing>

At S1001, initialization processing of a counter that counts the pixelsdetermined to have been falsified at S1010, to be described later, isperformed. Specifically, the count number (number of falsified pixels)of the counter is set to “0”.

At next S1002, normalization processing is performed for the scannedimage obtained at S812. This normalization processing is performed formatching the dynamic range between the scanned image and the renderingimage. For example, the brightest portion of the scanned image isgenerally the color of the paper of the reading-target printed materialand a value having some kind of density in principle. On the other hand,the brightest portion of the rendering image is the pixel whose pixelvalues are R=255, G=255, and B=255. Further, the darkest portion of thescanned image is generally black of ink or toner and a value having somekind of lightness due to reflected light in principle. On the otherhand, the darkest portion of the rendering image is the pixel whosepixel values are R=0, G=0, and B=0. As described above, there areoriginally differences in the brightest color and in the darkest colorbetween both the images. Further, in a case where the printed materialis output in color, there is also a difference in tint between bothimages. For example, as regards the most vivid red that can be printed,compared to the pixel values (R=255, G=0, B=0) indicating the most vividred on the rendering image, the saturation in the scanned image is low.Consequently, normalization is performed for the values (RGB values) ofeach pixel of the scanned image by using formula (1) to formula (3)below and new pixel values (Rnorm, Gnorm, Bnorm) are found.

$\begin{matrix}{{Rnorm} = {\left( {R - {Rd}} \right)/\left( {{Rw} - {Rd}} \right) \times 255}} & {{formula}(1)}\end{matrix}$ $\begin{matrix}{{Gnorm} = {\left( {G - {Gd}} \right)/\left( {{Gw} - {Gd}} \right) \times 255}} & {{formula}(2)}\end{matrix}$ $\begin{matrix}{{Bnorm} = {\left( {B - {Bd}} \right)/\left( {{Bw} - {Bd}} \right) \times 255}} & {{formula}(3)}\end{matrix}$

By the normalization processing using formula (1) to formula (3)described above, the RGB values of the brightest color (white) of thescanned image are R=255, G=255, and B=255 and the RGB values of thedarkest color (black) are R=0, G=0, and B=0.

At next S1003, filter processing is performed for the scanned image forwhich the normalization processing has been performed. The filterprocessing is processing to perform stronger edge enhancement in orderto make easy the comparison with the rendering image.

At S1004 that follows, processing to remove the image patternrepresenting the embedded information from the scanned image for whichthe filter processing has been performed. In the image to be printed,which is generated at S205 in the flow in FIG. 2 described previously, adifference from the original document image (image of the electronicdocument that is the authentic original document) has occurred due tothe embedding processing (S203). Consequently, in order to remove thedifference as much as possible, this processing is performed.Specifically, processing to subtract the pattern data embedded by theembedding processing from the scanned image is performed. Due to this,it is possible to put the scanned image close to the state before theembedding processing is performed. In the present embodiment, this isimplemented by adding a value to each pixel of the scanned image, thevalue being obtained by embedding each value in the masks in FIG. 4 andFIG. 6 described previously by “−1”.

Next, at S1005, processing to compare the scanned image from which theembedded information has been removed and the rendering image isperformed. Specifically, processing to compare the rendering image andthe scanned image from which the embedded information has been removedfor each pixel and find difference values (ΔR, ΔG, ΔB) expressed byformula (4) to formula (6) below is performed.

$\begin{matrix}{{\Delta R} = {❘{{{{R\lbrack x\rbrack}\lbrack y\rbrack}{of}{rendering}{image}} - {{{R\lbrack x\rbrack}\lbrack y\rbrack}{of}{scanned}{image}}}❘}} & {{formula}(4)}\end{matrix}$ $\begin{matrix}{{\Delta G} = {❘{{{{G\lbrack x\rbrack}\lbrack y\rbrack}{of}{rendering}{image}} - {{{G\lbrack x\rbrack}\lbrack y\rbrack}{of}{scanned}{image}}}❘}} & {{formula}(5)}\end{matrix}$ $\begin{matrix}{{\Delta B} = {❘{{{{B\lbrack x\rbrack}\lbrack y\rbrack}{of}{rendering}{image}} - {{{B\lbrack x\rbrack}\lbrack y\rbrack}{of}{scanned}{image}}}❘}} & {{formula}(6)}\end{matrix}$

Next, at S1006, whether or not the difference values (ΔR, ΔG, ΔB)obtained at S1005 exceed threshold values is determined. In the presentembodiment, the difference values (ΔR, ΔG, ΔB) are compared withthreshold values (Rth, Gth, Bth) provided in advance for each channel ofRGB and in a case where one of ΔR, ΔG, and ΔB exceeds the correspondingthreshold value, the processing advances to S1007 and none of ΔR, ΔG,and ΔB exceeds each corresponding threshold value, the processingadvances to S1008. The threshold value is determined in view of thecharacteristics and the like of the scanner unit and the printingapparatus and in a case of the present embodiment, it is sufficient toset values, for example, such as Rth=Gth=Bth=64.

At S1007, the count value of the counter, which indicates the number offalsified pixels, is incremented (+1). After the increment of thecounter, the processing advances to S1008. Then, at S1008, whether ornot the comparison of the pixel value is completed for all the pixels isdetermined. In a case where there is an unprocessed pixel, theprocessing returns to S1005 and the processing is continued and in acase where the comparison of the pixel value is completed for all thepixels, the processing advances to S1009.

At S1009, whether or not the count value of the counter, which indicatesthe number of falsified pixels, exceeds a threshold value is determined.It is sufficient to set the threshold value in this case to a value, forexample, such as 3% of the total number of pixels, by supposing asituation in which dust is mixed in at the time of obtaining the scannedimage. In a case where the count value exceeds the threshold value, theprocessing advances to S1010 and in a case where the count value doesnot exceed the threshold value, the processing advances to S1011.

At S1010, it is determined that the results of the falsification checkprocessing indicate that there is no falsification and this processingis exited. On the other hand, at S1011, it is determined that theresults of the falsification check processing indicate that there isfalsification and this processing is exited.

The above is the contents of the falsification check processing. In thepresent embodiment, the comparison is performed for each pixel, but thecomparison is not limited to this and it may also be possible to performthe comparison with a larger size, for example, such as comparingaverage values for each cluster of a plurality of pixels. In a casewhere the falsification check processing is completed, the processingadvances to S818 in FIG. 8.

Explanation is returned to the flowchart in FIG. 8.

At S818, the processing is branched in accordance with the results ofthe falsification check processing of the bitmap image obtained at S812.In a case where there is no falsification, the processing advances toS819 and in a case where there is falsification, the processing advancesto S820. In a case where the results of the falsification checkprocessing indicate that there is falsification, it may also be possibleto give a notification to a user by displaying a message or the like tothe effect that “the falsified document is about to be copied”. Due tothis, the user is given a chance to select abortion of the copy work orthe like.

Next, at S819, processing to add information indicating being a copy ofthe “printed material of the authentic original document” is added tothe bitmap image obtained at S812 is performed. Both FIG. 11 and FIG. 12each show an example in which character information of “COPY” is addedand a bitmap image 1100 in FIG. 11 is a case where character informationis added as a background image and a bitmap image 1200 in FIG. 12 is acase where character information is added as a foreground image. In eachcase, it is made possible to easily recognize that the printed materialis not the “printed material of the authentic original document” but aprinted material that is copied and output by applying an embeddingmethod (for example, modulation is performed for each value of RGB)whose capability of being visually recognized is high compared to theembedment of document ID information. Further, at the time of the addprocessing, it may also be possible to give a notification to a user bydisplaying a message or the like to the effect that “the printedmaterial of the authentic original document is about to be copied”. Dueto this, the user is given a chance to select abortion of the copy workor the like.

At next S820, an image to be printed is generated based on the bitmapimage obtained at S812 or the bitmap image for which the add processinghas been performed at S819. This processing corresponds to S205 in theflow in FIG. 2 described previously and there is no difference inparticular, and therefore, explanation is omitted. At S821 that follows,print processing using the image to be printed, which is generated atS820, is performed.

The above is the flow of the processing at the time of copying theprinted material of the authentic original document. In place ofperforming the notification processing, such as displaying a message orthe like, at S814, S816, S818, and S819, it may also be possible toperform control to automatically abort the copy processing itself ateach point in time. Due to this, it is possible to save effort and timeto check the intention of a user each time.

Further, it can be said that the information indicating of being a copy,which is added at S819, is information guaranteeing that the authenticoriginal document is not falsified, that is, so-called “informationindicating that the contents are formal and being a copy”. Consequently,it may also be possible to add character string information more clearlyrepresenting that the copy-target printed material is an authenticdocument, such as the “copied material of the printed material of theauthentic original document”. Further, in a case as well where it isdetermined that there is falsification at S818, it may also be possibleto cause the processing to advance to generation of an image to beprinted (S820) after adding characters, such as “informal (falsified)copied material”.

Further, it may also be possible to update the authentic document IDinformation extracted from the copy-target “printed material of theauthentic original document” to document ID information indicating ofbeing a copied material and then embed the updated document IDinformation in the bitmap image again and print and output the bitmapimage at S820. Due to this, in a case where the printed material inwhich the updated document ID information is embedded, which is outputat S820, is about to be copied, it is made possible to notify a user ofthat. At this time, it is sufficient to obtain and store together thedocument ID information indicating of being a copied material in theformat, such as the format of reserved ID information, at the time ofobtaining the document ID information (S202) in the print processing ofthe authentic original document. Due to this, it is made possible tonotify a user that the printed material is a copied material without theneed to request the external PC for collation.

As above, according to the present embodiment, in a case where the“printed material of the authentic original document” is copied,information indicating this fact is added as visible information whoserecognizability is high, and therefore, it is made possible for a userto easily recognize that it is the “copied material of the authenticoriginal document”. Further, in a case where a user further attempts tocopy the “copied material of the authentic original document” obtainedby the above-described copy processing, it is also possible to notifythe user of the fact by detecting the added information indicating ofbeing a copied material with the copy machine.

Modification Example 1

In the above-described embodiment, the example is explained in which thedocument ID information is multiplexed for each area of 8×8 pixels andembedded. By this method, the predetermined pattern is formed in thehigh-frequency area within the image, and therefore, it is made possibleto embed information in such a manner that a user is unlikely tovisually recognize the information. However, the method of embeddinginformation is not limited to this and for example, it may also bepossible to turn document ID information into a QR code and embed the QRcode in such a manner that the QR code is unlikely to be visuallyrecognized.

FIG. 13A shows an example of a QR code and FIG. 13B shows an actualprint pattern corresponds thereto. In the example in FIG. 13B, thepattern is such that one dot is formed for each area of 8×8 pixels. Thedot corresponding to a black pixel 1301 in the QR code in FIG. 13Acorresponds to one dot 1302 in the print pattern shown in FIG. 13B. Thatis, at the position corresponding to the white pixel in the QR code inFIG. 13A, the dot of the print pattern is not formed. As a flow ofspecific processing to implement this, first, document ID information isturned into a QR code in the embedding processing (S204) in the flow inFIG. 2 described previously and then the QR code is converted intopattern data of a group of discrete dots and embedded in the renderingimage for each predetermined area. Then, in the next image to be printedgeneration processing (S205), by causing the discrete dots to be formedonly in Y ink, it is possible to make the dots more unlikely to bevisually recognized.

Then, in the copy processing of the printed material in which documentID information is embedded by the method of the present modificationexample, it is sufficient to extract a QR code pattern formed by yellowdots in units of 8×8 pixels from the bitmap image having read thedocument ID information and extract the document ID information bydecoding the QR code pattern.

Further, as an embedment method of other than a QR code, for example, itmay also be possible to perform embedding by performing threshold valuemodulation at the time of, for example, quantization processing (seeJapanese Patent Laid-Open No. 2006-270972).

Modification Example 2

In the explanation so far, it is premised that the document IDinformation indicating authenticity is embedded in such an aspect inwhich a user is as unlikely to visually recognize the document IDinformation as much as possible in the print processing of the authenticoriginal document. However, it may also be possible to embed document IDinformation in such an aspect (for example, modulation is performed alsofor the R value and the G value that cause the variation in density ofeach ink of CMYK to be large) in which a user can visually recognize thedocument ID information with ease.

In that case, in the copy processing thereof, it may also be possible toprint the rendering image that is generated at the time of preprocessingof the falsification check processing (S817) as it is, or print thebitmap image from which embedded data has been removed (S1004) as it is.By performing printing by one of these methods, a printed material inwhich document ID information is not embedded is output. In this case,from the user side, it seems that pattern data that can be visuallyrecognized is not printed in the paper white area of the printedmaterial obtained by copying, and therefore, it is possible to easilyrecognize that the printed material is not the “printed material of theauthentic original document”. Further, the embedded data does not existin the printed material that is copied and output, and therefore, in acase where the printed material become further the target of copying,the determination results at S814 are No without fail.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

According to the technique of the present disclosure, it is possible toeasily determine the printed material of the electronic document provedas the authentic original document and the copied material thereof.

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the disclosure is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2021-024356, filed Feb. 18, 2021 which is hereby incorporated byreference wherein in its entirety.

What is claimed is:
 1. An image processing apparatus having a copyfunction, the image processing apparatus comprising: a memory thatstores a program; and a processor that executes the program to perform:obtaining a scanned image by scanning a copy-target printed material;extracting embedded information from the scanned image; generating animage to be printed based on the scanned image; and performing printprocessing using the image to be printed, wherein in the generating, ina case where it is confirmed that the copy-target printed material is anauthentic document by embedded information extracted in the extracting,an image to be printed that is the scanned image to which informationindicating being a copied material is added is generated.
 2. The imageprocessing apparatus according to claim 1, wherein the information thatis added is visible information.
 3. The image processing apparatusaccording to claim 2, wherein the information being the copied materialis information indicating being a copied material of an authenticdocument.
 4. The image processing apparatus according to claim 3,wherein in the generating, further, in a case where it is not confirmedthat the copy-target printed material is an authentic document by theextracted embedded information, an image to be printed to whichinformation indicating being a copied material of an unauthenticdocument is added is generated.
 5. The image processing apparatusaccording to claim 1, wherein in the extracting, the embeddedinformation is extracted by detecting a predetermined pattern from thescanned image.
 6. The image processing apparatus according to claim 5,wherein the embedded information is represented by binary datarepresented by a combination of 0 and 1 and the predetermined pattern isa pattern indicating 0 or
 1. 7. The image processing apparatus accordingto claim 5, wherein the embedded information is represented by a QR codeand the predetermined pattern is a pattern of discrete dotscorresponding to the QR code.
 8. The image processing apparatusaccording to claim 1, connected with an external device that managesdocument data in association with information indicating authenticity ofa document via a network, wherein the processor executes the program toperform obtaining collation results by requesting the external devicefor collation between extracted embedded information and informationindicating authenticity of the managed document and in the generating,in a case where it is confirmed that the copy-target printed material isan authentic document by collation results received from the externaldevice, print data to which information indicating being a copiedmaterial of an authentic document is added is generated.
 9. The imageprocessing apparatus according to claim 1, wherein in the extracting, ina case where it is not possible to extract the embedded information fromthe scanned image or in a case where it is not confirmed that thecopy-target printed material is an authentic document by extractedembedded information, the processor executes the program to performnotifying a user of that.
 10. The image processing apparatus accordingto claim 1, wherein in the extracting, in a case where it is notpossible to extract the embedded information from the scanned image orin a case where it is not confirmed that the copy-target printedmaterial is an authentic document by extracted embedded information, theprocessor executes the program to perform aborting the print processing.11. The image processing apparatus according to claim 1, wherein in thegenerating, the image to be printed is generated by embeddinginformation indicating being a copied material in the scanned image inplace of information indicating authenticity of a document indicated bythe embedded information extracted from the scanned image.
 12. The imageprocessing apparatus according to claim 11, wherein in a case where theembedded information extracted from the copy-target printed material isinformation indicating being the copied material, the processor executesthe program to perform notifying a user that the copy-target printedmaterial is a copied material.
 13. A control method of an imageprocessing apparatus having a copy function, the control methodcomprising: an obtaining step of obtaining a scanned image by scanning acopy-target printed material; an extraction step of extracting embeddedinformation from the scanned image; a generation step of generating animage to be printed based on the scanned image; and a printing step ofperforming print processing using the image to be printed, wherein atthe generation step, in a case where it is confirmed that thecopy-target printed material is an authentic document by embeddedinformation extracted at the extraction step, an image to be printedthat is the scanned image to which information indicating being a copiedmaterial is added is generated.
 14. A non-transitory computer readablestorage medium storing a program for causing a computer to perform acontrol method of an image processing apparatus having a copy function,the control method comprising: an obtaining step of obtaining a scannedimage by scanning a copy-target printed material; an extraction step ofextracting embedded information from the scanned image; a generationstep of generating an image to be printed based on the scanned image;and a printing step of performing print processing using the image to beprinted, wherein at the generation step, in a case where it is confirmedthat the copy-target printed material is an authentic document byembedded information extracted at the extraction step, an image to beprinted that is the scanned image to which information indicating beinga copied material is added is generated.